Healthy BMI by age: does the number change as you get older?

For adults, the healthy BMI range is 18.5 to 24.9 at every age, for women and men alike. What changes is how to read it. Research on people over 65 finds no extra risk in the overweight range, children are measured on growth charts, and people of Asian background face higher risk at a lower BMI. A worked example at 5 ft 4 in (163 cm).

Oct 2, 2026 · By Calcelate Team

The short answer is no. For adults, the healthy body mass index (BMI) range is 18.5 to 24.9 at 25, at 50 and at 80. The CDC states plainly that its adult categories apply to everyone 20 and older “regardless of age, sex, or race”. The World Health Organization uses the same lines.

So why do so many people search for a healthy BMI for women over 50, or over 70? Because the number does not mean quite the same thing at every stage of life. Below is what changes, and what does not, worked through for one height.

The adult categories

These are the CDC and WHO lines for adults. They do not move with age or sex. A woman of 5 ft 4 in (163 cm) has a healthy weight of 108 to 145 lb (49 to 66 kg) whether she is 30 or 70.

One height, three readings

Take a woman who is 5 ft 4 in (163 cm). The table below shows her BMI at seven weights, and how three sources would read it.

At 150 lb (68 kg) her BMI is 25.7. By the standard adult categories that is overweight, at any age. With the lower cut-offs the WHO suggests for Asian populations, it is in the increased-risk range. And for a woman over 65, research suggests it carries no extra risk at all. All three readings are correct; they answer different questions.

Over 65: a slightly higher BMI may be better

The official categories do not change at 65, but the research behind them looks different. A 2014 meta-analysis of 32 studies followed almost 200,000 people aged 65 and over for an average of 12 years. It found that being overweight was not linked to a higher risk of death. The risk was higher below a BMI of 23 and only began to rise above 33. The authors suggest keeping an eye on weight in older people with a BMI under 23, so that any weight loss with a cause that can be treated is caught early.

In the example above, 120 lb (54 kg) is a BMI of 20.6: healthy by the standard categories, but in the range where that study found higher risk for older people. That does not mean an older person should try to gain weight; it means a BMI in the low 20s is not automatically the goal it might be at 40, and losing weight without trying is worth raising with a doctor.

Women over 50 and 60

The healthy range does not change for women after 50, 60 or 70. What BMI cannot show is where the weight sits. The National Heart, Lung, and Blood Institute adds a waist measurement: a waist of more than 35 inches (89 cm) for women, or more than 40 inches (102 cm) for men, increases health risk. To measure, stand and put the tape around your middle just above the hip bones, and read it just after you breathe out. Two women with the same BMI can carry very different risk depending on that number.

Children and teens

Under 20, BMI is not read against the adult lines at all. Children are still growing, and body fat changes with age and differs between girls and boys. The CDC compares a child’s BMI with other children of the same age and sex and gives a percentile:

• under the 5th percentile: underweight;
• 5th to under the 85th: healthy weight;
• 85th to under the 95th: overweight;
• 95th and over: obesity.

Our BMI calculator uses the adult categories and tells you when the person is under 20.

People of Asian background

At the same BMI, people of Asian descent tend to have more body fat and a higher risk of type 2 diabetes and heart disease. A WHO expert consultation proposed lower action points for Asian populations: increased risk from 23 and high risk from 27.5. In the example above, that moves 140 lb (64 kg), a BMI of 24.0, out of the healthy range. The BMI calculator has a switch for these cut-offs.

In the UK

The NHS uses the same adult categories, and applies the lower lines more widely: for people from South Asian, Chinese, other Asian, Middle Eastern, Black African or African-Caribbean backgrounds, a BMI of 23 to 27.4 counts as overweight and 27.5 or higher as obese.

The short answer

For every adult from 20 up, a healthy BMI is 18.5 to 24.9, and the lines are the same for women and men. Age changes how to read the number, not the number itself: over 65, a BMI in the mid to high 20s is not linked to higher risk in research, and a waist measurement tells you more than BMI alone at any age. If you want to know how many calories it takes to keep or change your weight, the TDEE calculator works from your height, weight, age and activity.